It will be readily seen that there must be, at all times, twelve checks in each square on the board, counting both tool and workman's checks. Reference to the tool rack will show how many tools have been issued and what workman has them. The advantage of this system is that it is practically automatic. A perfect record of the movement of tools is kept without the necessity of making entries on cards or in books. Another method of operating the double check system is to supply the workman with a number of tool checks, these checks bearing the workman's number. When he wishes to withdraw a tool he presents one of these checks, which is hung above the tool rack. One of the checks bearing the tool number is then placed on the hook under the workman's number on the board. One disadvantage of this system is that the workman is more liable to lose checks than he is to lose tools. Theoretically, the number of checks in possession of the workman at any time, added to the number of checks on his hook on the board, should equal the number originally given to him. If, however, he loses a check, it usually means a dispute, as the workmen naturally does not feel that he should be penalized by failure to return a check on which no tool has been issued. All things considered, the method first described is probably the most satisfactory. [Illustration: Fig 36. Special Stock Record of Machine Tools] =32. Tool Records.= While the system described above furnishes a complete check on the tools, it should be supplemented by a record which will serve as a perpetual record of values. The tools may be divided into two classes, namely, _machine_ tools, and _small_ tools, each requiring a somewhat different form of record. Fig. 36 is the form of record for machine tools, this being on either a card or loose leaf. One card is used for each tool required. The record shows the name of the tool, the number, size, purpose for which used, and date made. Below this is a complete record of the cost, showing quantity manufactured, cost of material, labor, and burden. When tools are destroyed a record is made showing date and value, and the balance on hand is debited in the last column. For small tools Fig. 37 is used. This record shows much the same information as for machine tools. The special feature of this form is the record of quantities received from time to time, number delivered and returned, and number destroyed. As a rule, it is unnecessary to record deliveries on this card, though in the case of some very expensive tools, it may be advisable to do so. Both of the forms referred to above are filed in the same manner as other stores─record cards. The main divisions would be by name, or by departments, with subdivisions according to size. [Illustration: Fig. 37. Inventory Form for Small Tools]